1. Field of the Invention
The present invention relates to a laminar film material wherein a base film layer of polyimide material is covered on both major surfaces by a particular, heat sealable, fluorinated polymer material having a filler of inorganic pigment. The film material of the invention is especially useful as an insulating wire wrap material with excellent high temperature properties.
2. Description of the Prior Art
Polyimide film materials have often been used with other materials--films or coatings--to provide a laminate or composite exhibiting a combination of the properties of the component materials. Laminar films have, for example, been made having polyimide as a base layer and an unpigmented heat sealable fluorinated polymer as a coating thereon. Such laminar films have also been made having an alpha-chloromethylphenyltrialkoxy silane as an adhesive promoter between the polyimide and the fluoropolymer layers.
Laminar films have been made wherein polyimide is the base layer, each side of the polyimide is coated with a different fluoropolymer, and, as a means for identifying the fluoropolymer, in one of the fluoropolymers there is a colorant pigment material.